Energy from organic fuels Chapter 15 Energy from organic fuels

The Need for Energy fuel: any substance from which energy is obtained. Examples:? How have things changes? Organic fuels: contain carbon compounds, examples: Hydrocarbon: compounds composed of only hydrogen and carbon, example: methane (a lot of them end in “ane” Methane, Ethane, Octane…. The octane rating of gasoline is derived from a formula based on the amount of energy contained in the gas compared to pure iso-octane.

Butane isomers: same number of atoms, different structure.

Organic fuels often contain other chemicals (the bad part usually for us anyhow), example: sulfur or lead Called impurities, many contribute to pollution. Fossil Fuels When organisms die, not all of the energy they had stored was released. When buried, and you add pressure, typically the organisms energy is not loss. Therefore: fuels derived from the remains of organisms that lived long ago are fossil fuels. Examples: coal, petroleum, and natural gas.

Coal Generated by organisms that died, covered in sediment, and with added pressure and heat formed coal. Chemically changed, and water removed (via pressure) become solid rock (coal) Over time, hydrogens and oxygen's are removed, concentrating the carbon (concentration of coal is directly related to the amount of energy available). This concentration is how we categorize different types of coal materials. Peat Not technically a type of coal Lowest value of energy available High water content, low percent of carbon First stage of coal formation Looks kind of like decaying wood The youngest of these categories Gives off a large amount of smoke (due to high water concentration)

Lignite Second stage of coal formation Soft, brown coal composed of about 40% carbon Burns quickly, very little smoak Must be mined (peat does not have to be mined) Bituminous Coal Soft coal, 85 % carbon Must be mined Even more pure, burns hotter Used by many power plants Most abundant coal mined in US Anthracite Purest coal, 95% carbon Shiny, black, often deeper underground than any other Burns the hottest, least amount of smoke Most expensive to acquire as well.

Petroleum - crude oil, and a liquid fossil fuel non-renewable Formed from microscopic protists, plants, and animals Millions of years to form Trapped in pocked beneath nonporous rock (with water and natural gas) Can be under very high pressure (hence the term “gusher” when drilled into it. Worlds most important resource. Used to make a variety of products after being refined Heat homes Produce electricity Grease and lubricants Asphalt for roads Many types of plastics

Natural Gas Often found trapped above petroleum pools Mostly gaseous hydrocarbons Methane is the primary Others include: propane, nitrogen, and helium Used instead of coal or oil because it burns cleaner (stoves, heaters, etc…) Really good because it does not have to be converted to electricity, can be burned directly Because of this, more efficient and less expensive to use Often NG is considered a waste product at the oil platform and is burned off.

Other organic fuels Biomass Fuels (is a fuel formed from the products of living organisms) Wood Still relied on heavily in developing nations Advantages: renewable Disadvantages: lots of smoke that is high is carbon dioxide, tree reduction can cause more erosion. Garbage About 2/3 of the material in garbage can be burned. Some cities in the US already take advantage of this (using the heat to generate steam, thus produce electricity) Methane “swamp gas” Decaying garbage dumps also produce methane (both are being harvested and used same ways as natural gas) Cows are the number one releasing agent of methane (both ends) but this is much harder to use.

Alcohol bioconversion: converting organic materials into fuels Sugarcane and corn are used to make alcohol. Ethanol is the primary alcohol being produced right now Good: renewable Bad: not as much energy available as from regular gas Gasohol: mixture of 4 parts gasoline to one part ethanol.